Symantec Visual Cafe for Java 2.5/symantec-visual-cafe-2.5-database-dev-edition.iso/Extras/ODesign/SetupPSE.exe/data.z/CollDemo.java

Java Source | 1997-04-23 | 5.5 KB | 192 lines

package COM.odi.demo.collections;

/**
 *      <H3>Copyright (C) Object Design Inc. 1996, 1997</H3>
 *
 * This is the source code of the basic example used in the
 * documentation of ObjectStore Java Pro.
 */

// import the persistent collections package which we created
import pcollections.*;

// import the ObjectStore API
import COM.odi.*;

import java.util.NoSuchElementException;
import java.util.Enumeration;

/**
 * CollDemo is a simple test of the persistence-capability of the
 * HashedSet, HashedMap, Dynarray, RBTree classes from the
 * persistent version of the collections library.
 */

class CollDemo {

  /* This sets the maximum size of the HashedMap, HashedSet, Dynarray
   * classes.  RBTree may be larger.
   */
  static final int maxCollectionSize = 20;

  public static void main(String[] argv) {
    if (argv.length != 1) {
      System.out.println("usage: CollDemo <dbname>");
      return;
    }

    ObjectStore.initialize(null, null);
    Database db = null;
    try {
      db = Database.open(argv[0], ObjectStore.OPEN_UPDATE);
    } catch (DatabaseNotFoundException ex1) {
      db = Database.create(argv[0], 0777);
    }

    Transaction tx = Transaction.begin(ObjectStore.UPDATE);

    try {
      /* Check to see if the roots exist yet.  If not,
     DatabaseRootNotFound will be thrown */
      db.getRoot("Dynarray");

      displayCollections(db);

      /* start a new transaction for the update phase */
      tx.commit();
      tx = Transaction.begin(ObjectStore.UPDATE);

      maintainCollections(db);

    } catch (DatabaseRootNotFoundException dbrex) {

      System.out.println("Populating the database...");

      /* Create collections objects */
      HashedMap hashedMap = new HashedMap();
      HashedSet hashedSet = new HashedSet();
      Dynarray dynarray = new Dynarray();
      RBTree rbtree = new RBTree();

      /* Create roots so that we can find them in later transactions */
      db.createRoot("HashedMap", hashedMap);
      db.createRoot("HashedSet", hashedSet);
      db.createRoot("Dynarray", dynarray);
      db.createRoot("RBTree", rbtree);

      /* Populate the collections */
      for (int i = 0; i<maxCollectionSize; i++)
    maintainCollections(db);
    }

    tx.commit();

    db.close();
  }

  /**
   * Add or subtract elements to/from the collections.  This method
   * selects a random number to decide whether to add/subtract.
   */
  static void maintainCollections(Database db) {

    /* lookup the collection roots */
    HashedMap hashedMap = (HashedMap) db.getRoot("HashedMap");
    HashedSet hashedSet = (HashedSet) db.getRoot("HashedSet");
    Dynarray dynarray = (Dynarray) db.getRoot("Dynarray");
    RBTree rbtree = (RBTree) db.getRoot("RBTree");

    /* Select a random integer */
    Integer integer =
      new Integer((int) (Math.random() * maxCollectionSize));

    try {
      String string = (String) hashedMap.at(integer);

      /* Remove the integer from the collections */
      System.out.println ("removing " + integer);

      hashedMap.removeAt(integer);
      hashedSet.exclude(integer);
      dynarray.removeAt(dynarray.firstIndexOf(string));

      for (int j=0; j<string.length(); j++)
       rbtree.removeOneOf(new Character(string.charAt(j)));

    } catch (NoSuchElementException e) {
      /* add the integer to the collections */
      String string  = integer.toString();

      System.out.println ("adding " + integer);

      /* HashedMap will contain a mapping of Integer to String */
      hashedMap.putAt(integer, string);

      /* HashedSet will contain Integers */
      hashedSet.include(integer);

      /* Dynarray will include the string */
      dynarray.insertAt(0, string);

      for (int j=0; j<string.length(); j++)
    rbtree.add(new Character(string.charAt(j)));
    }
  }

  /**
   * Display the contents of the current collections.
   */
  static void displayCollections(Database db) {

    /* lookup the collection roots */
    HashedMap hashedMap = (HashedMap) db.getRoot("HashedMap");
    HashedSet hashedSet = (HashedSet) db.getRoot("HashedSet");
    Dynarray dynarray = (Dynarray) db.getRoot("Dynarray");
    RBTree rbtree = (RBTree) db.getRoot("RBTree");

    /* Display the HashedSet */

    System.out.println("HashedSet contains " +
               hashedSet.size() + " elements:");
    for (Enumeration hse = hashedSet.elements(); hse.hasMoreElements();) {
      Integer integer = (Integer) hse.nextElement();
      System.out.print("  " + integer);
    }
    System.out.println();

    /* Display the HashedMap */

    System.out.println("HashedMap contains " +
               hashedMap.size() + " elements:");

    boolean first = true;
    for (Enumeration hse = hashedSet.elements(); hse.hasMoreElements();) {
      Integer integer = (Integer) hse.nextElement();
      String string = (String) hashedMap.at(integer);
      System.out.print("  " + integer + "->\"" + string + "\"");
    }
    System.out.println();

    /* Display the Dynarray */

    System.out.println("Dynarray contains " +
               dynarray.size() + " elements:");
    for (Enumeration dae = dynarray.elements(); dae.hasMoreElements();) {
      String string = (String) dae.nextElement();
      System.out.print("  \"" + string + "\"");
    }
    System.out.println();

    /* Display the RBTree */

    System.out.println("RBTree contains " +
               rbtree.size() + " elements:");
    for (Enumeration rbe = rbtree.elements(); rbe.hasMoreElements();) {
      Character character = (Character) rbe.nextElement();
      System.out.print("  \'" + character + "\'");
    }
    System.out.println();
  }
}